Virus removal efficiency of ceramic water filters: effects of bentonite turbidity

2013 ◽  
Vol 14 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Cameron Farrow ◽  
Edward McBean ◽  
Hamidreza Salsali

Ceramic water filters (CWFs) are utilized in many developing countries as point-of-use (POU) water treatment devices, to reduce waterborne pathogens in potable water. Virus removal efficiencies of several CWFs are investigated under various influent conditions using MS2 (ATCC: 15597-B1) as a surrogate phage for human enteric viruses. The addition of bentonite turbidity (6–8 NTU) in the influent source water showed increased viral removal efficiency of CWFs by 0.1–0.2 log compared to tests involving clear (<1 NTU) influents. Trials employing an applied clay cake layer, formed using highly turbid influent source water (100 NTU) and no cleaning regime between trials, resulted in viral removal efficiency values of 1.5–2.5 log, compared to 0.2–0.5 log during non-obstructed trials.

2011 ◽  
Vol 9 (2) ◽  
pp. 306-311 ◽  
Author(s):  
Hamidreza Salsali ◽  
Edward McBean ◽  
Joseph Brunsting

Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.


2014 ◽  
Vol 5 (1) ◽  
pp. 28-38 ◽  
Author(s):  
L. Guerrero-Latorre ◽  
M. Rusiñol ◽  
A. Hundesa ◽  
M. Garcia-Valles ◽  
S. Martinez ◽  
...  

Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (2–4 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the objective of improving the viral removal efficiencies of ceramic water filters, new prototypes with different oxide compositions and firing atmospheres have been developed and evaluated. For removal efficiencies human adenoviruses, MS2 bacteriophage and Escherichia coli were quantified in all prototypes. A new model of CWF that was fired in a reductive atmosphere presented virus and bacteria removal efficiencies greater than 3.0 log and 2.5 log, respectively, which would fulfill the viral targets that are recommended by the WHO. Ceramic characterization of the selected filters, which were fired in a reductive atmosphere, showed that a larger specific surface area than those of control filters and higher fraction of a positive Z-potential fraction are the most likely explanations for this increase in virus removal.


2010 ◽  
Vol 10 (3) ◽  
pp. 286-295 ◽  
Author(s):  
H. M. Murphy ◽  
M. Sampson ◽  
K. Farahbakhsh ◽  
E. McBean

Unless significant advances are made in the water and sanitation sector, it is unlikely that Cambodia will meet the United Nations Millennium Development Goal (MDG) target #7 for water and sanitation. Point-of-use technologies (POU), also termed “household water treatment technologies”, have been identified as successful options for providing safe water to rural households. Ceramic water filters and BioSand filters are two major POU technologies that are currently implemented across Cambodia. This paper presents data on the microbial performance of these two technologies in the field on various Cambodian source waters. In addition, data are presented on the occurrence of nitrite in treated water. Results showed that 61% and 88% of BioSand filters and ceramic filters, respectively, produced water in the low risk range for E. coli as defined by the WHO (0–10 CFU/100 mL). In addition, 83% of BioSand filters and 75% of ceramic filters were not meeting the WHO guideline value for chronic exposure to nitrite in drinking water (0.2 mg/L).


2009 ◽  
Vol 43 (14) ◽  
pp. 3559-3565 ◽  
Author(s):  
Angela R. Bielefeldt ◽  
Kate Kowalski ◽  
R. Scott Summers

2012 ◽  
Vol 47 (1) ◽  
pp. 429-435 ◽  
Author(s):  
Ryan W. Schweitzer ◽  
Jeffrey A. Cunningham ◽  
James R. Mihelcic

2012 ◽  
Vol 10 (2) ◽  
pp. 209-220 ◽  
Author(s):  
Lisa M. Casanova ◽  
Adam Walters ◽  
Ajith Naghawatte ◽  
Mark D. Sobsey

Sri Lanka was devastated by the 2004 Indian Ocean tsunami. During recovery, the Red Cross distributed approximately 12,000 free ceramic water filters. This cross-sectional study was an independent post-implementation assessment of 452 households that received filters, to determine the proportion still using filters, household characteristics associated with use, and quality of household drinking water. The proportion of continued users was high (76%). The most common household water sources were taps or shallow wells. The majority (82%) of users used filtered water for drinking only. Mean filter flow rate was 1.12 L/hr (0.80 L/hr for households with taps and 0.71 for those with wells). Water quality varied by source; households using tap water had source water of high microbial quality. Filters improved water quality, reducing Escherichia coli for households (largely well users) with high levels in their source water. Households were satisfied with filters and are potentially long-term users. To promote sustained use, recovery filter distribution efforts should try to identify households at greatest long-term risk, particularly those who have not moved to safer water sources during recovery. They should be joined with long-term commitment to building supply chains and local production capacity to ensure safe water access.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 285
Author(s):  
Nkosinobubelo Ndebele ◽  
Joshua N. Edokpayi ◽  
John O. Odiyo ◽  
James A. Smith

In this study, we report on field testing of ceramic water filters (CWFs) fabricated using a new method of silver application (using silver nitrate as a raw material) compared to conventionally manufactured CWFs (fabricated with silver nanoparticles). Both types of filters were manufactured at the PureMadi ceramic filter production facility in Dertig, South Africa. Thirty households received filters fabricated with silver nitrate (AgNO3), and ten of those households were given an extra filter fabricated with silver nanoparticles. Filter performance was quantified by measurement of total coliform and Escherichia coli (E. coli) removal and silver residual concentration in the effluent. Silver-nitrate CWFs had removal efficiencies for total coliforms and E. coli of 95% and 99%, respectively. A comparison of the performance of silver-nitrate and silver-nanoparticle filters showed that the different filters had similar levels of total coliform and E. coli removal, although the silver nitrate filters produced the highest average removal of 97% while silver nanoparticles filters recorded an average removal of 85%. Average effluent silver levels were below 10 ppb for the silver-nitrate and silver-nanoparticle filters, which was significantly below the Environmental Protection Agencies of the United States (EPA) and World Health Organization (WHO) secondary guidelines of 100 ppb. Silver-nitrate filters resulted in the lowest effluent silver concentrations, which could potentially increase the effective life span of the filter. A cost analysis shows that it is more economical to produce CWFs using silver nitrate due to a reduction in raw-material costs and reduced labor costs for production. Furthermore, the production of silver-nitrate filters reduces inhalation exposure of silver by workers. The results obtained from this study will be applied to improve the ceramic filtration technology as a point-of-use (POU) water treatment device and hence reduce health problems associated with microbial contamination of water stored at the household level.


Author(s):  
S. A. Osemeahon ◽  
J. O. Okechukwu ◽  
B. J. Dimas

The lack of clean water sources due to pollution and industrialisation is a major problem in many countries including Nigeria. To overcome this challenge, various methods have been adopted including phytoremediation treatment. This study evaluates dried duckweed an aquatic plant and its removal efficiency in comparison with other locally available treatment materials. This was achieved by formulating ceramic water filters (C.W.F) categorized into four different types- clay and kaolin(P1), clay, kaolin and sawdust(P2), clay, kaolin and charcoal(P3) and clay, kaolin and duckweed(P4). These filters were subjected to contaminated water and the following physicochemical parameters Colour, pH, Conductivity(Ec), Fluoride(F-), Magnesium(Mg2+), Nitrites(NO2-), Sulphates (SO42-), Ammonia (NH3) and Total Suspended Solids (TSS) and Total Nitrogen were determined before and after filtration. In all the ceramic water filters, the filter improved by duckweed showed the best removal efficiency of Colour – 100%, Conductivity(Ec) -72.60%, Fluoride(F)- 99.82%, Magnesium(Mg2+)- 51.68% Nitrites(NO2-)-92.34, Sulphates (SO42-)- 46.09%, Ammonia (NH3)-98.75%, and Total Suspended Solids (TSS)- 85.43% and Total Nitrogen (TN) -83.79% indicating that duckweed is capable of adsorbing inorganic and organic pollutants from water.


2009 ◽  
Vol 7 (3) ◽  
pp. 404-412 ◽  
Author(s):  
Joe Brown ◽  
S. Proum ◽  
M. D. Sobsey

The effectiveness of point-of-use water treatment may be limited by declining use over time, particularly when water treatment is introduced via targeted intervention programmes. In order to evaluate the long-term uptake and use of locally produced ceramic water filters in rural Cambodia, we visited households that had received filters as part of NGO-subsidized distribution programmes over a 4 year period from 2002 to 2006. Of the more than 2,000 filters distributed, we visited 506 randomly selected households in 13 villages spanning three provinces to assess filter time in use and to collect data on factors potentially correlated with long-term use. Results indicate that filter use declined at the rate of approximately 2% per month after implementation, largely owing to breakages, and that, controlling for time since implementation, continued filter use over time was most closely positively associated with: related water, sanitation and hygiene practices in the home; cash investment in the technology by the household; and use of surface water as a primary drinking water source.


Sign in / Sign up

Export Citation Format

Share Document